It took brass balls to release an album with that title in that year, and Haken are apologetic yet firm that the virus of the title here does not refer to Covid-19 (it was released in July 2020 after being delayed). Instead, it continues the musical and lyrical themes from predecessor Vector, about psychological issues and mysterious doctors and kings, set to a djent-infused prog metal mix that's more than pleasing to the ears. As with its predecessor, hooks are a big part of the writing, particularly in high-pitched singer Ross Jenkins' vocal lines, but the band are very fond of the big, Dream Theater-y melody as well as the more complex little instrumental syncopations between. Opener Prosthetic is a great example of this, an earworm chorus with plenty of chuggy, downright King Crimson-gone-industrial metallic clamour surrounding it, seeming far shorter than its nearly six minute running time.

And from then on Virus moves through a variety of songs if not particularly stretching their sounds, from the immediately-following Invasion with its lilting vocal intro like recent material from Leprous before opening into an electronic-infused piece of proggy rock that comes across as a more aggressive Tool. Ten minuter Carousel dips into classic Opeth material with some of the riffing, stretching the song length and doing so well, allowing more of a focus to fall on drummer Ray Hearne's skills (although one major point against the album, the too-clinical production, does fall most harshly on his plastic-sounding drums in general). Sure, none of this is particularly new or even original given how incestuous in sound modern prog metal can be, yet Haken are so good by now (and let's remember, this is over a decade and six albums into their career) at putting everything together to make sharp, listenable songs that it makes Virus a compelling listen.

Even the more typically djenty-feeling songs like The Strain and outright near-falsetto ballad Canary Yellow are great and beautiful respectively, and the lengthy multi-part epic Messiah Complex is just under seventeen minutes of prog bliss. It moves from Dream Theater-y metallic precision through symphonic-enhanced bursts of grandeur, including softer vocal-led meandering and harder metallic crushing that reaches almost Strapping Young Lad levels of heaviness at points including a slight dip into avant-garde territory, before bringing it all back together for a catchy finale. After that, closing melancholic snippet Only Stars feels a little too much like an afterthought and could easily have been left off this fifty-minute-plus album without harming it. Still, as a whole this is a remarkably good follow-up to Vector that only just missed the year-end awards - less instantaneously catchy and unique, but a more thoughtful and mature take on this djent-infused direction for Haken.